the differences between API 5CT N80 and L80 oil casing

API 5CT N80 oil casing is an important equipment in oil drilling, main equipment includes drill pipe, tubing and casing, drill collar and small diameter drilling tube.
API 5CT L80 oil casing is also an important equipment in oil drilling, main steel grade includes H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P-110, Q-125.

Heat treatment
PSL1: it requires N80 and L80 can be rolled stated delivery
PSL2: L80 oil casing is usually used in acid environment, N80 is commonly used in general environment.

Performance
L80 is a kind of oil well pipe with good resistance carbon dioxide corrosion, good corrosion resistance to sea water, therefore, this performance makes L80 into the common oil casing pipe in ocean oil and gas drilling. N80 steel oil casing is important equipment for oil drilling.

Mechanical Properties Test
N80: Tensile strength ≥517MPa; Yield strength: 379MPa ~ 552MPa; Minimum elongation: 19%
L80: Tensile strength ≥655MPa; Yield strength: 379MPa ~ 552MPa; Minimum elongation: 15%

Impact Test
N80 and L80 impact test: the min size of the sample lateral impact energy 20J; the smallest full-size sample longitudinal impact energy 27J.

Wall Thickness Detection
PSL1: Measuring the wall thickness, there are no coverage requirements for N80 and L80 oil casing;
PSL2: For all pipes, N80 and L80 shall be one or more of the criteria specified in 0.15.5 tested to find the inner surface of the outer surface of the pipe and can receive the level of L4 longitudinal imperfections.